How to see memory on Xiaomi Mi 9: RAM, ROM and hidden partitions

Why check the memory on Xiaomi Mi 9?

The Xiaomi Mi 9, released in 2019, is still popular with users thanks to its powerful hardware: Snapdragon 855 processor, up to 12 GB of RAM and up to 256 GB of ROM. However, even such features can become a bottleneck over time — especially if you actively install applications, shoot videos in 4K or play modern games.

✔️ Optimize performance – if RAM is constantly clogged, the phone begins to “brake” and forcibly close applications. ✔️ Control space on the disk – system updates, cache and junk files can “eat” tens of gigabytes unnoticed. ✔️ Diagnose problems – for example, if the smartphone suddenly restarts when the memory is 90%+.

In this article, we’ll look at all the ways you can check memory on the Xiaomi Mi 9, including hidden system partitions that don’t show up in standard settings, learn how to view not only user memory, but also service data (such as partition /vendor or /recovery), and how to interpret the digits you receive.

Method 1: Standard Android settings

The easiest method is to use built-in MIUI tools, which is suitable for quickly checking the total ROM volume and free space, but does not show details by partition or RAM.

Instructions:

1. Open the Settings app** (cog icon).
2. Go to the About Phone section. → Warehouse.
3. Wait for the data to be downloaded (it can take up to 10 seconds).

Here you'll see:

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If the Storage section displays less memory than the specifications (e.g. 112GB instead of 128GB), that’s fine. Part of the space is occupied by system partitions (/system, /boot, etc.) that are not available to the user.

Limitations of the method:

Method 2: Viewing RAM through Task Manager

To find out how much RAM (RAM) is currently in use, as well as what applications it takes, use the built-in MIUI Manager:

Steps:

1. Open “Settings”** → Applications → Task Manager.

Below is a list of active processes, sorted by the amount of RAM occupied.

Example of data interpretation:

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If free RAM is constantly less than 500 MB, the smartphone will begin to forcibly close applications, which will lead to slowdowns and “outs”.

Important: MIUI aggressively controls RAM, so even with free memory, the system can shut down background processes. This is normal behavior for battery optimization.

Method 3: Using applications for deep diagnostics

Xiaomi’s standard tools don’t show the full picture. For detailed memory analysis (including hidden partitions and chip temperature), we recommend third-party utilities:

Top.-3 applications:

Instructions for AIDA64:

1. Download the app from Google Play.
2. Open the System section → Memory.
3. Scroll down to the Storage block** – all partitions will be displayed here, including hidden ones: /system – system files (about 3-5 GB) /data – user data (main section) /cache – update cache (up to 1 GB) /persist – communication module data (10–50 MB)

The advantages of third-party utilities:

Method 4: View memory through ADB (for advanced users)

If you want the most accurate data (for example, to debug or modify firmware), use Android Debug Bridge (ADB), which requires a connection to a computer, but gives access to all partitions, including service ones.

Step-by-step:

1. Turn on Developer Mode** on Xiaomi Mi 9: 🔧 Go to Settings. → The phone. 🔧 Press 7 times on the line Version MIUI, until you have become a developer, you have become a developer!. 🔧 Back to Settings → Additionally. → For developers and activate debugging by USB.

command-line

terminal

adb shell


df -h

The result will be similar to this one:

/dev/block/mmcblk0p53  112G   45G   67G  40% /data


/dev/block/mmcblk0p48  512M  120M  392M  23% /cache




/dev/block/mmcblk0p41   30M   22M  8.0M  73% /persist

Transcript of commands:

Install Xiaomi drivers on PC

Download the ADB platform (for example, from Google)

Enable debugging over USB on your phone

Confirm trust in the computer on the smartphone screen-->

⚠️ Note: Do not change files in sections /system, /boot or /recovery This can lead to a "brick"** (inoperability) of the device!

Method 5: Engineering menu (hidden settings)

The Xiaomi Mi 9, like other smartphones on the Qualcomm Snapdragon, has a hidden engineering menu where you can check memory at a low level, a method suitable for diagnosing hardware problems (for example, damage to flash memory).

How to open the engineering menu:

1. Open the phone application** (call).
2. Enter the code ##4636##

What you'll see:

Example of normal performance for Xiaomi Mi 9:

⚠️ Note: If the engineering menu displays Read Fail or bad blocks, this may indicate physical wear of flash memory, in which case we recommend backing up the data and contacting the service center.

Frequent memory problems on Xiaomi Mi 9 and their solutions

Even on flagship smartphones like the Mi 9, users are facing typical memory problems, and we'll look at some of the most common cases and ways to fix them.

Problem 1: “Memory is full” but there are few files

Reason: System cache, updates or junk files take up space.

Problem 2: Apps fly out at low memory

Reason: MIUI aggressively releases RAM, killing background processes.

Problem 3: After the update, there is less memory

Reason: Newer versions of MIUI take up more space (e.g. MIUI 14 weighs 1-2GB more than MIUI 12).

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If the memory problem persists after resetting, it may indicate a hardware defect (flash memory wear or controller damage).

FAQ: Answers to Frequent Questions